PNEUMONECTOMY
Pneumonectomy was first successfully performed in 1933 by Evarts Graham. The procedure was carried out for bronchogenic carcinoma in a fellow physician, James Gilmore, who eventually outlived his surgeon. The event is a milestone in surgical history. The technique of pneumonectomy has been improved and standardized in the intervening years, and the results are quite gratifying when the operation is carefully performed in appropriately selected cases. Current indications are chiefly as an operation for cure for lung cancer (usually centrally located) or for a destroyed lung as a result of infection or trauma. Palliative pneumonectomy is generally not warranted unless it is directed at alleviation of sepsis or control of recurrent hemorrhage. Before embarking upon resection of an entire lung, the surgeon must have a histologic diagnosis and a full assessment of the patient’s cardiopulmonary reserve; little is gained if the pneumonectomized patient survives but has severe respiratory disability.
Pneumonectomy, as now practiced, is routinely performed
via a standard posterolateral thoracotomy incision. The anterior approach has
long been abandoned because of inadequate access to critical hilar structures;
the posterior approach, with the patient in a face-down or prone position (once
favored because it afforded better control of secretions from the operative
side) is no longer required as a result of improvements in selective lung
ventilation.
Posterolateral thoracotomy is performed with the patient
securely fixed in a lateral recumbent position. An inflatable bag or bolster
under the chest greatly improves access and exposure and is removed before
closure of the incision. A curved incision is made, starting midway between the
vertebral border of the scapula and the spine, clearing the angle of the
scapula by one to two fingerbreadths and continuing forward in a transverse
direction following the angle of the ribs to a submammary position. The
standard incision involves division of the entire latissimus dorsi muscle, but
the serratus anterior muscle can often be separated from its posterior border
and detached from anterior rib insertions, preserving its function. If greater
exposure is needed, especially cephalad, the skin incision is carried
superiorly, and the lower fibers of the trapezius and rhomboid muscles are
divided. With exposure of the subscapular space, the ribs are counted from the
first rib downward. Entry through the fifth intercostal space along the superior
border of the sixth rib is the standard approach to both pneumonectomy and any
lobectomy. It affords good access for proximal control of any hilar vessel.
Concern for optimal suprahilar exposure may necessitate a fourth interspace
incision; an infrahilar lesion can be approached through the sixth space,
although access to the proximal pulmonary artery may be compromised. Resection
of a segment of rib (shingling) or rarely an entire rib, customarily the fifth,
provides favorable exposure in older patients (who have less elastic chest
walls) and allows for an airtight closure of the chest wall. Insertion of a rib
spreader provides the exposure illustrated after any pleural adhesions present
are divided.
The hilum is carefully studied by both visual examination
and palpation for extension of tumor into the mediastinum a sign of advanced
disease that is not resectable. Infrequently, the pericardium must be opened to
complete this assessment. The superior mediastinum is similarly explored via an
incision through the parietal pleura dorsal to the superior vena cava.
Suspicious lymph nodes may be removed and submitted for frozen section, and
although nodes in this area may be removed with the lung, the presence of
extensive mediastinal lymphatic spread predicts a poor prognosis and may
influence the surgeon’s decision whether to proceed with pneumonectomy.
After the lesion has been determined to be resectable for
cure, hilar dissection is started. In general, the artery is divided first,
followed by the vein, then the bronchus, although there are exceptions. First
the lung is retracted posteriorly and inferiorly and the right main pulmonary
artery exposed behind the lower superior vena cava. Division of the uppermost
tributary of the right superior pulmonary vein may facilitate exposure. The
perivascular sheath is entered, and the artery is freed up by sharp and blunt
dissection using a right-angle or Semb clamp. The artery is then divided
between ligatures or with a vascular stapler, leaving a long proximal stump.
The superior pulmonary vein is similarly freed up and
divided, exposing the anterior aspect of the right main bronchus. Division of
any or all critical hilar structures can be accomplished with suture or
mechanical stapling devices.
The lung is then retracted superiorly and anteriorly to
expose the inferior pulmonary vein along the superior margin of the inferior
pulmonary ligament. This vessel also is exposed within its vascular sheath for
a suitable extent and divided, leaving a long proximal stump, because slippage
of the suture would cause catastrophic bleeding.
The right main bronchus is cleared and clamped after lymph nodes and areolar tissue have been swept distally onto the specimen. The bronchus is exposed to the level of the carina and a stapling device placed across it immediately below its origin. After the stapler has been fired, the bronchus is amputated distal to the line of staple closure and the lung removed from the chest. The bronchial stump is then tested under saline for air leakage by having the anesthesiologist apply positive airway pressure (20-25 cm H2O) via the endotracheal tube. The stump should be buttressed with vascularized tissue such as pericardium, intercostal muscle, or parietal pleura. Postoperatively the hemithorax can be drained for a short period of time (often 24 hours) and then the space can be allowed to fill with fluid. Monitoring of the fluid level by chest radiographs is important if there is ever concern for a bronchopleural fistula because the level may decrease if a fistula has developed.
